Method for assisting in stripping transition metal sulfide by expanding interlayer spacing through solvent vaporization
Through solvent vaporization, the layer spacing is expanded and combined with ultrasonic peeling technology, the problem of low single layer yield of transition metal sulfide in the prior art is solved, and a more efficient peeling effect is achieved.
Patent Information
- Application Number
- CN202510023882.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2025-04-01
AI Technical Summary
The existing liquid phase ultrasonic peeling technology is not sufficient to completely or completely destroy the van der Waals force between the layers of the bulk phase material, resulting in low single-layer yield of transition metal sulfides.
The transition metal sulfide is aided by dissolving the transition metal sulfide in the first solvent and evaporating it with heating, expanding the layer spacing, and then dissolving the residue in the second solvent and sonicating it with auxiliary peeling of the transition metal sulfide.
It effectively improves the single-layer yield of transition metal sulfide, and destroys the van der Waals force between layers more completely or completely than a single ultrasonic peel.
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Figure CN119735170A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of nano material preparation, and more specifically to a method for assisting the stripping of transition metal sulfides by expanding interlayer spacing through solvent vaporization. Background Art
[0002] Two-dimensional (2D) materials have a series of novel physical phenomena and chemical activities due to their limited electron motion dimensions and large specific surface area, showing physical, electronic and chemical properties that are completely different from their bulk forms. Typical two-dimensional layered materials include hexagonal boron nitride (h-BN), transition metal disulfides (TMDs), layered double hydroxides (LDHs), layered zeolites, two-dimensional polymers (such as covalent organic frameworks (COFs) and metal organic frameworks (MOFs)), and transition metal carbides or carbonitrides (Mxenes). Among them, transition metal disulfides (TMDs) have become a research hotspot in the field of materials science due to their environmental friendliness, excellent thermodynamic stability and outstanding optoelectronic properties.
[0003] In the prior art, liquid phase ultrasonic exfoliation technology is usually used to obtain a few or single layers of transition metal disulfide (TMDs) materials. This technology mainly uses cavitation bubbles generated by ultrasound, and assists solvents or surfactants to destroy the van der Waals force between the layers of bulk materials, so as to promote the exfoliation of a few-layer nanosheet from the bulk material, thereby obtaining a two-dimensional material. However, this technology is still not enough to completely or thoroughly destroy the van der Waals force between the layers of bulk materials, resulting in a low single-layer yield of transition metal sulfides. Summary of the invention
[0004] The purpose of the present invention is to provide a method for solvent vaporization to expand the interlayer spacing and assist in the exfoliation of transition metal sulfides, which is used to solve the technical problem that the existing liquid phase ultrasonic exfoliation technology is not enough to completely or thoroughly destroy the van der Waals force between the bulk material layers, resulting in low single-layer yield of transition metal sulfides. In view of this, the present invention is implemented through the following scheme.
[0005] The present invention provides a method for solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides, comprising: Dissolving a transition metal sulfide in a first solvent to obtain a first solution; the concentration of the transition metal sulfide in the first solution is 1-8 mg / ml; Heating the first solution until the first solvent in the first solution is completely volatilized to obtain a residue; After dissolving the residue in a second solvent, ultrasonic treatment is performed to obtain a dispersion; The supernatant of the dispersion is collected; the supernatant contains the stripped transition metal sulfide.
[0006] Compared with the prior art, the method of the present invention for expanding the interlayer spacing by solvent vaporization to assist in the stripping of transition metal sulfides expands the interlayer spacing of transition metal sulfides by solvent vaporization, thereby assisting the ultrasonic stripping technology in stripping transition metal sulfides. Specifically, the above-mentioned first solvent is used to expand the transition metal sulfide during the process of heating to volatilize it, dissolving the transition metal sulfide in the first solvent, and then heating the first solution. The heating temperature and time are controlled within a reasonable range, so that the first solvent can be gradually volatilized. The first solvent is filled in the interlayer of the transition metal sulfide during the vaporization (evaporation) process, thereby expanding its interlayer spacing. After the first solvent is completely volatilized, the above-mentioned residue is obtained, and the residue is the transition metal sulfide after the interlayer spacing is expanded. Furthermore, the transition metal sulfide (i.e., the above-mentioned residue) with the enlarged interlayer spacing is subjected to ultrasonic stripping. Specifically, after the residue is dissolved in a second solvent, ultrasonic treatment is performed to obtain a dispersion. During the ultrasonic stripping process, the interlayer spacing of the transition metal sulfide is enlarged after the first solution is heated, which provides favorable conditions for the ultrasonic stripping process. That is, during the ultrasonic stripping process, the van der Waals force between the layers of the transition metal sulfide (i.e., the above-mentioned residue) can be more completely or thoroughly destroyed (more completely or thoroughly than a single ultrasonic stripping), effectively increasing the single-layer yield of the transition metal sulfide. Through the above-mentioned technical solution of the present invention, the technical problem that the existing liquid-phase ultrasonic stripping technology is not sufficient to completely or thoroughly destroy the van der Waals force between the layers of the bulk material, resulting in a low single-layer yield of the transition metal sulfide is solved.
[0007] Furthermore, in the method of solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides of the present invention, the first solvent includes acetone, methanol, ethyl acetate and diethyl ether.
[0008] Furthermore, in the method of solvent evaporation to expand interlayer spacing and assist in exfoliation of transition metal sulfides of the present invention, during the heating treatment of the first solution, the heating temperature is 30-80° C. and the heating time is 8-25 minutes.
[0009] Furthermore, in the method of solvent evaporation to expand interlayer spacing and assist in exfoliation of transition metal sulfides of the present invention, the second solvent includes N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.
[0010] Furthermore, in the method of solvent evaporation to expand interlayer spacing and assist in exfoliation of transition metal sulfides of the present invention, the ultrasonic treatment time is 2 to 6 hours and the ultrasonic amplitude is 15 to 45%.
[0011] Furthermore, in the method for solvent evaporation to expand interlayer spacing and assist in exfoliation of transition metal sulfides of the present invention, the mass of the residue required for every 1 ml of the second solvent in the dispersion is 1-5 mg.
[0012] Furthermore, in the method of solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides of the present invention, before collecting the supernatant of the dispersion, the method further comprises: The dispersion is centrifuged to remove the unstripped transition metal sulfide in the dispersion and obtain a supernatant.
[0013] Furthermore, in the method of solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides of the present invention, the centrifugal treatment is carried out in a centrifuge, the rotation speed of the centrifuge during the centrifugal treatment is 6000-10000 rpm, and the centrifugal time is 15-45 minutes.
[0014] Furthermore, in the method of the present invention for assisting the exfoliation of transition metal sulfides by expanding the interlayer spacing through solvent evaporation, the boiling point of the first solvent is 30-80°C.
[0015] Furthermore, in the method of solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfide of the present invention, the transition metal sulfide comprises tungsten disulfide or molybdenum disulfide; and / or, The transition metal sulfide has a size of 27 μm×20 nm. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a schematic diagram for comparing the ultraviolet spectra of the supernatants in Comparative Example 1 and Examples 1 to 4 of the present invention; Figure 2 Schematic diagram for comparing the concentration and yield of the supernatant in Comparative Example 1 and Examples 1 to 4 of the present invention; Figure 3 Schematic diagram showing the appearance comparison of the supernatant in Comparative Example 1 and Examples 1 to 4 of the present invention; Figure 4 This is a schematic diagram of atomic force microscopy (AFM) characterization of the supernatant in Example 1 of the present invention; Figure 5 for Figure 4 Schematic diagram of the measured thickness at the locations marked 1, 2 and 3; Figure 6 This is a statistical diagram of the size of nanosheets in the dispersion of Example 1 of the present invention; Figure 7 Schematic diagram of Raman test comparison of the supernatant of Example 1 of the present invention and Comparative Example 1; Figure 8 Schematic diagram of X-ray diffraction (XRD) comparison between Example 1 of the present invention and Comparative Example 1; Fig. 9 This is a schematic diagram of the stability test of the supernatant in Example 1 of the present invention; Fig.10 It is a schematic diagram for comparing the ultraviolet spectra of the supernatants in Comparative Example 2, Example 5 and Example 6 of the present invention; Fig.11 It is a schematic diagram comparing the concentration and yield of the supernatant in Comparative Example 2, Example 5 and Example 6 of the present invention; Fig.12 Schematic diagram for comparing the appearance of the supernatant in Comparative Example 2, Example 5 and Example 6 of the present invention. DETAILED DESCRIPTION
[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0018] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0019] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.
[0020] In the prior art, liquid phase ultrasonic exfoliation technology is usually used to obtain a few or single layers of transition metal disulfide (TMDs) materials. This technology mainly uses cavitation bubbles generated by ultrasound, and assists solvents or surfactants to destroy the van der Waals force between the layers of bulk materials, so as to promote the exfoliation of a few-layer nanosheet from the bulk material, thereby obtaining a two-dimensional material. However, this technology is still not enough to completely or thoroughly destroy the van der Waals force between the layers of bulk materials, resulting in a low single-layer yield of transition metal sulfides.
[0021] In order to solve the above technical problems, the present invention provides a method for solvent vaporization to expand the interlayer spacing and assist in the exfoliation of transition metal sulfides, comprising: Dissolving a transition metal sulfide in a first solvent to obtain a first solution; the concentration of the transition metal sulfide in the first solution is 1-8 mg / ml; Heating the first solution until the first solvent in the first solution is completely volatilized to obtain a residue; After dissolving the residue in a second solvent, ultrasonic treatment is performed to obtain a dispersion; The supernatant of the dispersion is collected; the supernatant contains the stripped transition metal sulfide.
[0022] In the case of adopting the above technical scheme, the method of the present invention for solvent vaporization to expand the interlayer spacing and assist in the stripping of transition metal sulfides expands the interlayer spacing of transition metal sulfides by solvent vaporization, thereby assisting the ultrasonic stripping technology in stripping transition metal sulfides. Specifically, the above-mentioned first solvent is used to expand the transition metal sulfide during the process of heating to volatilize it, dissolving the transition metal sulfide in the first solvent, and then heating the first solution. The heating temperature and time are controlled within a reasonable range, so that the first solvent can be gradually volatilized. The first solvent is filled in the interlayer of the transition metal sulfide during the vaporization (evaporation) process, thereby expanding its interlayer spacing. After the first solvent is completely volatilized, the above-mentioned residue is obtained, and the residue is the transition metal sulfide after the interlayer spacing is expanded. Further, the transition metal sulfide (i.e., the above-mentioned residue) with the enlarged interlayer spacing is subjected to ultrasonic stripping. Specifically, after dissolving the residue in a second solvent, ultrasonic treatment is performed to obtain a dispersion. During the ultrasonic stripping process, since the interlayer spacing of the transition metal sulfide is enlarged after the first solution is heated, favorable conditions are provided for the ultrasonic stripping process. That is, during the ultrasonic stripping process, the van der Waals force between the layers of the transition metal sulfide (i.e., the above-mentioned residue) can be more completely or thoroughly destroyed (more completely or thoroughly than a single ultrasonic stripping), effectively improving the single-layer yield of the transition metal sulfide; illustratively, the concentration of the transition metal sulfide in the first solution can be 1 mg / ml, 3 mg / ml, 6 mg / ml or 8 mg / ml. illustratively, the transition metal sulfide includes tungsten disulfide or molybdenum disulfide, and the specification of the transition metal sulfide is 27 μm×20 nm; in another example, the transition metal sulfide can be tungsten disulfide or molybdenum disulfide. The technical solution of the present invention solves the technical problem that the existing liquid phase ultrasonic stripping technology is insufficient to completely or thoroughly destroy the van der Waals force between bulk material layers, resulting in low single-layer yield of transition metal sulfides.
[0023] As described above, the first solvent is filled in the interlayers of the transition metal sulfide during the gasification (volatization) process, thereby expanding the interlayer spacing. In order to enhance this effect of the first solvent (expanding the interlayer spacing), the type of the first solvent should also be controlled; illustratively, the first solvent includes acetone, methanol, ethyl acetate and diethyl ether; in another example, the first solvent may be acetone, methanol, ethyl acetate or diethyl ether.
[0024] It should also be understood that in the method of solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides of the present invention, as described above, the first solvent is filled in the interlayer of the transition metal sulfide during the vaporization (volatilization) process, thereby expanding its interlayer spacing. In order to completely volatilize the first solvent in a shorter time, the boiling point of the first solvent should be controlled in a lower range, or the temperature of the heating treatment should be controlled in a higher range, or the temperature of the heating treatment is the boiling point of the first solvent used; illustratively, the boiling point of the first solvent can be 30~80°C, and the temperature of the heating treatment can also be 30~80°C; in another example, the boiling point of the first solvent can be 30°C, 50°C or 80°C, and the temperature of the heating treatment can be 30°C, 50°C or 80°C; further, when the temperature of the heating treatment is 30~80°C, the heating treatment time can be 8~25 minutes, and illustratively, the heating treatment time can be 8 minutes, 15 minutes or 25 minutes.
[0025] Furthermore, in the method of solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides of the present invention, after dissolving the residue (i.e., the transition metal sulfide after the interlayer spacing is expanded) in a second solvent, ultrasonic treatment is performed to obtain a dispersion. In this process, the second solvent serves as a solvent for liquid-phase ultrasonic stripping of the transition metal sulfide, and is also a storage solvent for the transition metal sulfide after the ultrasonic stripping is completed. Therefore, for the selection of the second solvent, on the one hand, it is required to facilitate the ultrasonic stripping of the transition metal sulfide, and on the other hand, it is also required to facilitate the storage of the transition metal sulfide; illustratively, the second solvent includes N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide; in another example, the second solvent can be N-methylpyrrolidone, N,N-dimethylformamide, or dimethyl sulfoxide; when the above-mentioned second solvent is used, since these second solvents have similar surface energies to the transition metal sulfide, the above two requirements can be met at the same time. In this process, for example, the mass of the residue required for every 1 ml of the second solvent can be 1-5 mg, the time of the ultrasonic treatment can be 2-6 hours, and the ultrasonic amplitude can be 15-45%; for another example, the mass of the residue required for every 1 ml of the second solvent can be 1 mg, 3 mg or 5 mg, the time of the ultrasonic treatment can be 2 hours, 4 hours or 6 hours, and the ultrasonic amplitude can be 15%, 30% or 45%.
[0026] As a possible implementation manner, in the method of the present invention for assisting the stripping of transition metal sulfides by expanding interlayer spacing by solvent vaporization, before collecting the supernatant of the dispersion, the method further comprises: The dispersion is centrifuged to remove the unstripped transition metal sulfide in the dispersion and obtain a supernatant.
[0027] When the above technical solution is adopted, in the method of the present invention for solvent vaporization to expand the interlayer spacing and assist in the exfoliation of transition metal sulfides, during the centrifugal treatment of the dispersion, the exfoliated, smaller transition metal sulfide nanosheets (usually present in the supernatant) can be effectively separated from the incompletely exfoliated, larger block or agglomerate materials, ensuring that the collected supernatant contains a higher proportion of the exfoliation product; illustratively, the centrifugal treatment is carried out in a centrifuge, and the rotation speed of the centrifuge during the centrifugal treatment is 6000~10000rpm, and the centrifugation time is 15~45 minutes; as another example, the rotation speed of the centrifuge can be 6000rpm, 8000rpm or 10000rpm, and the centrifugation time can be 15 minutes, 30 minutes or 45 minutes.
[0028] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific embodiments, but the content of the present invention is not limited to the following embodiments.
[0029] Unless otherwise specified, the raw materials used in the following examples are commercially available. Example 1
[0030] This embodiment provides a method for solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides, comprising: Step 1, dispersing tungsten disulfide powder in acetone, stirring for 30 minutes, and obtaining an acetone solution, wherein the concentration of tungsten disulfide powder in the acetone solution is 2 mg / ml; and the specification of the tungsten disulfide powder is 27 μm×20 nm; Step 2, heating the acetone solution to make it boil rapidly, continuing heating to completely evaporate the solvent to obtain tungsten disulfide residue; the heating temperature is 85° C., and the heating time is 15 minutes; Step 3, adding the tungsten disulfide residue to N-methylpyrrolidone, and ultrasonicating in a water bath for 5 minutes to dissolve the tungsten disulfide residue to form a dispersion of tungsten disulfide and N-methylpyrrolidone; wherein the temperature of the water bath is 25° C., the ultrasonic frequency is 20 kHz; and the mass of the residue required for each 1 ml of the N-methylpyrrolidone is 5 mg; Step 4, subjecting the dispersion obtained in step 3 to ultrasonic treatment; the ultrasonic treatment time is 4 hours and the amplitude is 30%; Step 5, centrifuging the dispersion after ultrasonic treatment in step 4 in a centrifuge for 30 minutes at a speed of 8000 rpm; collecting the supernatant, which is used for characterization and subsequent use or application. Example 2
[0031] This embodiment provides a method for solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides, comprising: S100, dispersing tungsten disulfide powder in methanol, stirring for 30 minutes, and obtaining a methanol solution, wherein the concentration of tungsten disulfide powder in the methanol solution is 2 mg / ml; and the specification of the tungsten disulfide powder is 27 μm×20 nm; S200, heating the methanol solution to make it boil rapidly, and continuing heating to completely evaporate the solvent to obtain tungsten disulfide residue; the heating temperature is 95° C., and the heating time is 20 minutes; S300, adding the tungsten disulfide residue to N-methylpyrrolidone, and subjecting the residue to ultrasonic treatment in a water bath for 5 minutes to dissolve the tungsten disulfide residue to form a dispersion of tungsten disulfide and N-methylpyrrolidone; wherein the temperature of the water bath is 25° C., the ultrasonic frequency is 20 kHz, and the mass of the residue required for each 1 ml of the N-methylpyrrolidone is 5 mg; S400, subjecting the dispersion of S300 to ultrasonic treatment; the ultrasonic treatment time is 4 hours and the amplitude is 30%; S500, centrifuging the dispersion treated with ultrasound in S400 in a centrifuge for 30 minutes at a speed of 8000 rpm; collecting the supernatant, which is used for characterization and subsequent use or application. Example 3
[0032] This embodiment provides a method for solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides, comprising: S100, dispersing tungsten disulfide powder in diethyl ether, stirring for 30 minutes, and obtaining a diethyl ether solution, wherein the concentration of tungsten disulfide powder in the diethyl ether solution is 2 mg / ml; and the specification of the tungsten disulfide powder is 27 μm×20 nm; S200, heating the ether solution to make it boil rapidly, continuing heating to completely evaporate the solvent to obtain tungsten disulfide residue; the heating temperature is 65° C., and the heating time is 20 minutes; S300, adding the tungsten disulfide residue to N-methylpyrrolidone, and subjecting the residue to ultrasonic treatment in a water bath for 5 minutes to dissolve the tungsten disulfide residue to form a dispersion of tungsten disulfide and N-methylpyrrolidone; wherein the temperature of the water bath is 25° C., the ultrasonic frequency is 20 kHz, and the mass of the residue required for each 1 ml of the N-methylpyrrolidone is 5 mg; S400, subjecting the dispersion of S300 to ultrasonic treatment; the ultrasonic treatment time is 4 hours and the amplitude is 30%; S500, centrifuging the dispersion treated with ultrasound in S400 in a centrifuge for 30 minutes at a speed of 8000 rpm; collecting the supernatant, which is used for characterization and subsequent use or application. Example 4
[0033] This embodiment provides a method for solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides, comprising: S100, dispersing tungsten disulfide powder in ethyl acetate, stirring for 30 minutes, and obtaining an ethyl acetate solution, wherein the concentration of tungsten disulfide powder in the ethyl acetate solution is 2 mg / ml; and the specification of the tungsten disulfide powder is 27 μm×20 nm; S200, heating the ethyl acetate solution to make it boil rapidly, and continuing heating to completely evaporate the solvent to obtain tungsten disulfide residue; the heating temperature is 108° C., and the heating time is 20 minutes; S300, adding the tungsten disulfide residue to N-methylpyrrolidone, and subjecting the residue to ultrasonic treatment in a water bath for 5 minutes to dissolve the tungsten disulfide residue to form a dispersion of tungsten disulfide and N-methylpyrrolidone; wherein the temperature of the water bath is 25° C., the ultrasonic frequency is 20 kHz, and the mass of the residue required for each 1 ml of the N-methylpyrrolidone is 5 mg; S400, subjecting the dispersion of S300 to ultrasonic treatment; the ultrasonic treatment time is 4 hours and the amplitude is 30%; S500, centrifuging the dispersion treated with ultrasound in S400 in a centrifuge for 30 minutes at a speed of 8000 rpm; collecting the supernatant, which is used for characterization and subsequent use or application. Example 5
[0034] This embodiment provides a method for solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides, comprising: S100, dispersing molybdenum disulfide powder in acetone, stirring for 30 minutes, and obtaining an acetone solution, wherein the concentration of molybdenum disulfide powder in the acetone solution is 2 mg / ml; and the specification of the molybdenum disulfide powder is 27 μm×20 nm; S200, heating the acetone solution to make it boil rapidly, continuing heating to completely evaporate the solvent to obtain a molybdenum disulfide residue; the heating temperature is 85° C., and the heating time is 15 minutes; S300, adding the molybdenum disulfide residue to N-methylpyrrolidone, and subjecting the molybdenum disulfide residue to ultrasonic treatment in a water bath for 5 minutes to dissolve the molybdenum disulfide residue to form a dispersion of molybdenum disulfide and N-methylpyrrolidone; wherein the temperature of the water bath is 25° C., the ultrasonic frequency is 20 kHz; and the mass of the residue required for each 1 ml of the N-methylpyrrolidone is 5 mg; S400, subjecting the dispersion of S300 to ultrasonic treatment; the ultrasonic treatment time is 4 hours and the amplitude is 30%; S500, centrifuging the dispersion treated with ultrasound in S400 in a centrifuge for 30 minutes at a speed of 8000 rpm; collecting the supernatant, which is used for characterization and subsequent use or application. Example 6
[0035] This embodiment provides a method for solvent vaporization to expand interlayer spacing and assist in stripping transition metal sulfides, comprising: S100, dispersing molybdenum disulfide powder in methanol, stirring for 30 minutes, to obtain a methanol solution, wherein the concentration of molybdenum disulfide powder in the methanol solution is 2 mg / ml; the specification of the molybdenum disulfide powder is 27 μm×20 nm; S200, heating the methanol solution to make it boil rapidly, continuing heating to completely evaporate the solvent to obtain a molybdenum disulfide residue; the heating temperature is 95° C., and the heating time is 15 minutes; S300, adding the molybdenum disulfide residue to N-methylpyrrolidone, and subjecting the molybdenum disulfide residue to ultrasonic treatment in a water bath for 5 minutes to dissolve the molybdenum disulfide residue to form a dispersion of molybdenum disulfide and N-methylpyrrolidone; wherein the temperature of the water bath is 25° C., the ultrasonic frequency is 20 kHz; and the mass of the residue required for each 1 ml of the N-methylpyrrolidone is 5 mg; S400, subjecting the dispersion of S300 to ultrasonic treatment; the ultrasonic treatment time is 4 hours and the amplitude is 30%; S500, centrifuging the dispersion treated with ultrasound in S400 in a centrifuge for 30 minutes at a speed of 8000 rpm; collecting the supernatant, which is used for characterization and subsequent use or application.
[0036] Comparative Example 1 The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides provided in this comparative example is different from that in Example 1, tungsten disulfide powder is directly added to N-methylpyrrolidone for ultrasonic treatment; the remaining steps and parameters are the same as those in Example 1.
[0037] Comparative Example 2 The method for solvent evaporation to expand interlayer spacing and assist in exfoliation of transition metal sulfides provided in this comparative example is different from that in Example 5, molybdenum disulfide powder is directly added to N-methylpyrrolidone for ultrasonic treatment; the remaining steps and parameters are the same as those in Example 5.
[0038] After obtaining the dispersion or supernatant of the above-mentioned embodiment and comparative example, the dispersion or supernatant is characterized or tested respectively. The characterization or test results are shown in Figure 1 To value Fig.12 ; specifically, see Figure 1 ,from Figure 1 It can be seen that the supernatant of Comparative Example 1 has a characteristic peak at 628nm, and Examples 1-4 have characteristic peaks at 623nm, and the characteristic peaks of Examples 1-4 are more obvious, indicating that Examples 1-4 and Comparative Example 1 both achieve the stripping of transition metal sulfides (Examples 1-4 are all tungsten disulfide), and the stripping effect of Examples 1-4 is better than that of Comparative Example 1; please refer to Figure 2 ,from Figure 2 It can be seen that compared with Comparative Example 1, the concentration and yield of the transition metal sulfides stripped from the supernatant of Examples 1 to 4 are higher, and the yield of Example 1 is as high as 61%. Figure 3 It can be seen that the color of the supernatant in Examples 1 to 4 is darker than that in Comparative Example 1, which also proves that the yield and concentration of Examples 1 to 4 are higher than those of Comparative Example 1; please refer to Figure 4 and Figure 5 , Figure 4 The numbers 1, 2 and 3 represent tungsten disulfide nanosheets. Figure 5 It can be seen that the thickness of the nanosheet is less than 2nm and the lateral size is 50nm-100nm, indicating that a single layer of tungsten disulfide has been successfully peeled off; Figure 6 It can be seen that most of the nanosheets obtained by peeling are concentrated below 5 layers, and the proportion of single layers accounts for 19%; Figure 7 It can be seen that the distance between the two peaks of Example 1 is reduced, indicating that Example 1 is more advantageous in reducing the thickness of the nanosheets than Comparative Example 1. Figure 8 It can be seen that the (002) crystal plane representing the longitudinal dimension in Example 1 is significantly reduced, indicating that Example 1 is more advantageous in reducing the thickness of the nanosheets than Comparative Example 1. Fig. 9 It can be seen that the supernatant of Example 1 has good stability within 100 days; Fig.10 It can be seen that Example 5 and Example 6 have characteristic peaks at 611nm and 685 respectively, indicating that the stripping is successful, and compared with Comparative Example 2, the stripping effects of Example 5 and Example 6 are better; Fig.11 It can be seen that compared with Comparative Example 2, the yields of Examples 5 and 6 are significantly improved, and the yield of Example 5 can reach 57.5%. Fig.12 It can be seen that the color of the supernatant of Example 5 and Example 6 is darker than that of Comparative Example 2, which also proves that Example 5 and Example 6 have higher concentrations and yields.
[0039] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.
[0040] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides, characterized in that: include: dissolving a transition metal sulfide in a first solvent to obtain a first solution; The concentration of the transition metal sulfide in the first solution is 1-8 mg / ml; Heating the first solution until the first solvent in the first solution is completely volatilized to obtain a residue; After dissolving the residue in a second solvent, ultrasonic treatment is performed to obtain a dispersion; The supernatant of the dispersion is collected; the supernatant contains the stripped transition metal sulfide.
2. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 1, characterized in that: The first solvent includes acetone, methanol, ethyl acetate and diethyl ether.
3. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 2, characterized in that: In the process of heating the first solution, the heating temperature is 30-80° C. and the heating time is 8-25 minutes.
4. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 3, characterized in that: The second solvent includes N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide.
5. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 4, characterized in that: The ultrasonic treatment time is 2 to 6 hours, and the ultrasonic amplitude is 15 to 45%.
6. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 5, characterized in that: In the dispersion, the mass of the residue required for each 1 ml of the second solvent is 1-5 mg.
7. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 6, characterized in that: Before collecting the supernatant of the dispersion, the method further comprises: The dispersion is centrifuged to remove the unstripped transition metal sulfide in the dispersion and obtain a supernatant.
8. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 7, characterized in that: The centrifugal treatment is carried out in a centrifuge. During the centrifugal treatment, the rotation speed of the centrifuge is 6000-10000 rpm and the centrifugal time is 15-45 minutes.
9. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 8, characterized in that: The boiling point of the first solvent is 30-80°C.
10. The method for solvent evaporation to expand interlayer spacing and assist in stripping transition metal sulfides according to claim 9, characterized in that: The transition metal sulfide comprises tungsten disulfide or molybdenum disulfide; and / or, The transition metal sulfide has a size of 27 μm×20 nm.